Theoretical and experimental investigations on corrosion control of 65Cu-35Zn brass in nitric acid by two thiophenol derivatives

Inhibitive performance of two thiophenol derivatives namely 4-aminothiophenol (4-ATP) and 4-amino phenol disulfide (4-APD) on corrosion behavior of 65Cu-35Zn brass in 0.5 M HNO3 was investigated. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) and also quantum chemical study were used. 4-APD showed higher efficiency at low temperatures while for higher temperatures the 4-ATP is more efficient. The inhibitors obey Langmuir isotherm and its adsorption is both chemical and physical type. Quantum chemical study reveals that the benzene ring, S and N atoms can be suitable sites for adsorption onto surface. Finally, an acceptable correlation between the theoretical and experimental inhibitor efficiency was acquired.